This study investigates how internalized sexual minority stigma and enacted sexual minority stigma in health care settings are associated with sexual health risk behaviors (SRBs) and the mediating role of infrequent routine health care and perceived stress among older gay and bisexual (G/B) men living with HIV disease. Survey responses from 135 sexually active older G/B men living with HIV were analyzed using hierarchical linear regression models. Results indicate that one fifth of G/B older adult men living with HIV are engaged in multiple SRBs. Internalized sexual minority stigma and enacted sexual minority stigma in health care settings are significantly associated with SRBs. The relationship between internalized sexual minority stigma and SRBs are mediated by infrequent routine health care and elevated levels of perceived stress. Improved primary and secondary prevention strategies are needed for the growing number of sexually active older G/B men.